Re: [PATCH v5 5/7] drm/aspeed: Add reset and clock for AST2600

Joel Stanley
2022-02-28T09:50:58Z

On Wed, 8 Dec 2021 at 01:34, Tommy Haung <tommy_huang@aspeedtech.com> wrote:
>
> From: tommy-huang <tommy_huang@aspeedtech.com>
>
> Add more reset and clock select code for AST2600.
> The gfx_flags parameter was added for chip caps idenified.

Can you tell me a bit more about the two reset lines:

What is the CRT reset line controlling?

What does the engine reset line control?

Can we use devm_reset_control_array_get() to get whichever are
specified in the device tree, so we don't need to have different logic
for the 2600 and earlier chips?

>
> Signed-off-by: tommy-huang <tommy_huang@aspeedtech.com>
> ---
> drivers/gpu/drm/aspeed/aspeed_gfx.h | 16 +++++++-
> drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c | 16 ++++++++
> drivers/gpu/drm/aspeed/aspeed_gfx_drv.c | 50 ++++++++++++++++++++++--
> 3 files changed, 77 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx.h b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> index 4e6a442c3886..2c733225d3c7 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx.h
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx.h
> @@ -8,7 +8,8 @@ struct aspeed_gfx {
> struct drm_device drm;
> void __iomem *base;
> struct clk *clk;
> - struct reset_control *rst;
> + struct reset_control *rst_crt;
> + struct reset_control *rst_engine;
> struct regmap *scu;
>
> u32 dac_reg;
> @@ -16,6 +17,7 @@ struct aspeed_gfx {
> u32 vga_scratch_reg;
> u32 throd_val;
> u32 scan_line_max;
> + u32 flags;
>
> struct drm_simple_display_pipe pipe;
> struct drm_connector connector;
> @@ -106,3 +108,15 @@ int aspeed_gfx_create_output(struct drm_device *drm);
> /* CRT_THROD */
> #define CRT_THROD_LOW(x) (x)
> #define CRT_THROD_HIGH(x) ((x) << 8)
> +
> +/* SCU control */
> +#define SCU_G6_CLK_COURCE 0x300
> +
> +/* GFX FLAGS */
> +#define RESET_MASK BIT(0)
> +#define RESET_G6 BIT(0)
> +#define CLK_MASK BIT(4)
> +#define CLK_G6 BIT(4)
> +
> +#define G6_CLK_MASK (BIT(8) | BIT(9) | BIT(10))
> +#define G6_USB_40_CLK BIT(9)
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> index 827e62c1daba..e0975ecda92d 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_crtc.c
> @@ -77,6 +77,18 @@ static void aspeed_gfx_disable_controller(struct aspeed_gfx *priv)
> regmap_update_bits(priv->scu, priv->dac_reg, BIT(16), 0);
> }
>
> +static void aspeed_gfx_set_clk(struct aspeed_gfx *priv)
> +{
> + switch (priv->flags & CLK_MASK) {
> + case CLK_G6:
> + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE, G6_CLK_MASK, 0x0);
> + regmap_update_bits(priv->scu, SCU_G6_CLK_COURCE, G6_CLK_MASK, G6_USB_40_CLK);
> + break;
> + default:
> + break;
> + }
> +}
> +
> static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv)
> {
> struct drm_display_mode *m = &priv->pipe.crtc.state->adjusted_mode;
> @@ -87,6 +99,8 @@ static void aspeed_gfx_crtc_mode_set_nofb(struct aspeed_gfx *priv)
> if (err)
> return;
>
> + aspeed_gfx_set_clk(priv);
> +
> #if 0
> /* TODO: we have only been able to test with the 40MHz USB clock. The
> * clock is fixed, so we cannot adjust it here. */
> @@ -193,6 +207,7 @@ static void aspeed_gfx_pipe_update(struct drm_simple_display_pipe *pipe,
> static int aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe)
> {
> struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> +
> u32 reg = readl(priv->base + CRT_CTRL1);
>
> /* Clear pending VBLANK IRQ */
> @@ -207,6 +222,7 @@ static int aspeed_gfx_enable_vblank(struct drm_simple_display_pipe *pipe)
> static void aspeed_gfx_disable_vblank(struct drm_simple_display_pipe *pipe)
> {
> struct aspeed_gfx *priv = drm_pipe_to_aspeed_gfx(pipe);
> +
> u32 reg = readl(priv->base + CRT_CTRL1);
>
> reg &= ~CRT_CTRL_VERTICAL_INTR_EN;
> diff --git a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> index d10246b1d1c2..59a0de92650f 100644
> --- a/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> +++ b/drivers/gpu/drm/aspeed/aspeed_gfx_drv.c
> @@ -64,6 +64,7 @@ struct aspeed_gfx_config {
> u32 vga_scratch_reg; /* VGA scratch register in SCU */
> u32 throd_val; /* Default Threshold Seting */
> u32 scan_line_max; /* Max memory size of one scan line */
> + u32 gfx_flags; /* Flags for gfx chip caps */
> };
>
> static const struct aspeed_gfx_config ast2400_config = {
> @@ -72,6 +73,7 @@ static const struct aspeed_gfx_config ast2400_config = {
> .vga_scratch_reg = 0x50,
> .throd_val = CRT_THROD_LOW(0x1e) | CRT_THROD_HIGH(0x12),
> .scan_line_max = 64,
> + .gfx_flags = 0,
> };
>
> static const struct aspeed_gfx_config ast2500_config = {
> @@ -80,6 +82,7 @@ static const struct aspeed_gfx_config ast2500_config = {
> .vga_scratch_reg = 0x50,
> .throd_val = CRT_THROD_LOW(0x24) | CRT_THROD_HIGH(0x3c),
> .scan_line_max = 128,
> + .gfx_flags = 0,
> };
>
> static const struct aspeed_gfx_config ast2600_config = {
> @@ -88,6 +91,7 @@ static const struct aspeed_gfx_config ast2600_config = {
> .vga_scratch_reg = 0x50,
> .throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
> .scan_line_max = 128,
> + .gfx_flags = RESET_G6 | CLK_G6,
> };
>
> static const struct of_device_id aspeed_gfx_match[] = {
> @@ -138,6 +142,44 @@ static irqreturn_t aspeed_gfx_irq_handler(int irq, void *data)
> return IRQ_NONE;
> }
>
> +static int aspeed_gfx_reset(struct drm_device *drm)
> +{
> + struct platform_device *pdev = to_platform_device(drm->dev);
> + struct aspeed_gfx *priv = to_aspeed_gfx(drm);
> +
> + switch (priv->flags & RESET_MASK) {
> + case RESET_G6:
> + priv->rst_crt = devm_reset_control_get(&pdev->dev, "crt");
> + if (IS_ERR(priv->rst_crt)) {
> + dev_err(&pdev->dev,
> + "missing or invalid crt reset controller device tree entry");
> + return PTR_ERR(priv->rst_crt);
> + }
> + reset_control_deassert(priv->rst_crt);
> +
> + priv->rst_engine = devm_reset_control_get(&pdev->dev, "engine");
> + if (IS_ERR(priv->rst_engine)) {
> + dev_err(&pdev->dev,
> + "missing or invalid engine reset controller device tree entry");
> + return PTR_ERR(priv->rst_engine);
> + }
> + reset_control_deassert(priv->rst_engine);
> + break;
> +
> + default:
> + priv->rst_crt = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> + if (IS_ERR(priv->rst_crt)) {
> + dev_err(&pdev->dev,
> + "missing or invalid reset controller device tree entry");
> + return PTR_ERR(priv->rst_crt);
> + }
> + reset_control_deassert(priv->rst_crt);
> + break;
> + }
> +
> + return 0;
> +}
> +
> static int aspeed_gfx_load(struct drm_device *drm)
> {
> struct platform_device *pdev = to_platform_device(drm->dev);
> @@ -163,6 +205,7 @@ static int aspeed_gfx_load(struct drm_device *drm)
> priv->vga_scratch_reg = config->vga_scratch_reg;
> priv->throd_val = config->throd_val;
> priv->scan_line_max = config->scan_line_max;
> + priv->flags = config->gfx_flags;
>
> priv->scu = syscon_regmap_lookup_by_phandle(np, "syscon");
> if (IS_ERR(priv->scu)) {
> @@ -186,13 +229,12 @@ static int aspeed_gfx_load(struct drm_device *drm)
> return ret;
> }
>
> - priv->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> - if (IS_ERR(priv->rst)) {
> + ret = aspeed_gfx_reset(drm);
> + if (ret) {
> dev_err(&pdev->dev,
> "missing or invalid reset controller device tree entry");
> - return PTR_ERR(priv->rst);
> + return ret;
> }
> - reset_control_deassert(priv->rst);
>
> priv->clk = devm_clk_get(drm->dev, NULL);
> if (IS_ERR(priv->clk)) {
> --
> 2.17.1
>